Modular furniture typically consists of a seat and backrest arrangement wherein the backrest is either permanently affixed to the seatrest or wherein the backrest and seatrest are associated with a basic frame structure. Usually, the backrest and seatrest are in the form of a rectangular or square, the backrest being permanently affixed to the sides of the seatrest with a variety of means for interconnecting one or more units to form a seating arrangement. Such seating combination is commonly referred to as a couch or playpen. Where the seat and backrest are permanently affixed to one another, there are inherent structural limitations in the construction of the seatrest and possible arrangement thereof with other modular units. Where the seatrest and backrest are not permanently affixed to one another, as typically shown in U.S. Pat. No. 2,793,685, the seatrest and backrest are releasably secured to a base frame to form a basic body support unit. The backrest portion in U.S. Pat. No. 2,793,685, however, is not capable of being interchangeably associated with each side of the seat support portion, and the unit itself is also limited in its possible configuration when associated with similar units.
The concept of modular furniture has evolved to allow a user to individually arrange units in such a way as is most suitable to his or her individual taste, taking into consideration available space. The prior art in providing square or rectangular units wherein the backrest is permanently affixed to the seatrest portion of the modular piece of furniture or wherein the backrest and seatrest portions are releasably secured to a base frame limits the possible modular configurations.